class DownloadTask(QObject):
status_changed = pyqtSignal(str)
aborted = pyqtSignal()
def __init__(self, url=None, target=None):
super().__init__()
self.url = url if url is not None else default_url
self.target = target if target is not None else target_prefix + self._available_target_for(
url)
self.status = 'Waiting'
self.thread_ = None
self.stopping = False
def __str__(self):
return 'Download task [URL = \'{}\', target = \'{}\', status = \'{}\']'.format(
self.url, self.target, self.status)
def start(self):
if self.stopping:
return
self.thread_ = DownloadThread(self.url, self.target)
self.thread_.completed.connect(self._on_completed)
self.thread_.aborted.connect(self._on_aborted)
self.thread_.failed.connect(self._on_failed)
self.thread_.progressed.connect(self._on_progressed)
self.thread_.start()
def stop(self):
if self.stopping:
return
self.stopping = True
if self.thread_.isRunning():
self.thread_.to_abort = True
else:
self._on_aborted(False)
def _on_completed(self):
self._change_status('Completed')
def _on_aborted(self, need_removal):
if need_removal:
self._remove_target()
self._change_status('Aborted')
self.stopping = False
self.aborted.emit()
def _on_failed(self, err_str):
if err_str:
self._change_status('Failed ({})'.format(err_str))
else:
self._change_status('Failed')
self._remove_target()
def _on_progressed(self, progress):
self._change_status('{:.2f}%'.format(progress * 100))
def _available_target_for(self, url):
res = url[url.rfind('/') + len('/'):]
separator_pos = res.rfind('.')
if separator_pos != -1:
filename, extension = res[:separator_pos], res[separator_pos +
len('.'):]
else:
filename, extension = res, ''
n = 0
while os.path.exists(res):
n += 1
res = self._make_res(filename, extension, n)
return res
def _make_res(self, filename, extension, n):
if n:
return filename + ' (' + str(n) + ').' + extension
return filename + '.' + extension
def _change_status(self, status):
self.status = status
self.status_changed.emit(status)
def _remove_target(self):
if os.path.exists(self.target):
os.remove(self.target)
